Based on the show's synopsis saying that all electric devices (not just electronics) have "mysteriously blacked out forever" I assumed the show would have some supernatural and/or inexplicable reason that there was no power.

Like Am_Fear_Liath_Mor, I don't buy that any natural or materialistic event could make electricity disappear from our landscape completely.
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Victory awaits him who has everything in order — luck, people call it. Defeat is certain for him who has neglected to take the necessary precautions in time; this is called bad luck. Roald Amundsen